Machine for vibrating, leveling and screeding concrete in a form

ABSTRACT

A self-propelled, automated machine for operating over a form to which concrete is introduced, the main functions of the machine being to level, vibrate and screed the concrete to provide a concrete slab without voids, and especially a slab in which both upper and lower surfaces, as well as opposite side edges and other sectional configurations are finished.

United States Patent [191 Matson June 18, 1974 1 MACHINE FOR VIBRATING,LEVELING AND SCREEDING CONCRETE IN A FORM Primary Examiner-MarionParsons, Jr.

[5 7] ABSTRACT A self-propelled, automated machine for operating over aform to which concrete is introduced, the main functions of the machinebeing to level, vibrate and screed the concrete to provide a concreteslab without voids, and especially a slab in which both upper and lowersurfaces, as well as opposite side edges and other sectionalconfigurations are finished.

7 Claims, 10 Drawing Figures [76] Inventor: Carl G. Matson, 401 E.Central Blvd., Kewanee, 111. 61443 [22] Filed: Aug. 2, 1972 [211 App].No.: 277,379

[52] US. Cl. 404/114, 404/120 [51] Int. Cl. E01c 19/48 [58] Field ofSearch 404/114, 119, 118, 120; 164/260; 425/424, 456

[56] References Cited UNITED STATES PATENTS 2,054,263 9/1936 McCrery404/119 2,219,247 10/1940 Jackson 404/114 2,430,816 11/1947 Jackson404/114 2,636,719 4/1953 OConnor.... 425/456 3,015,260 l/1962 Pelsue404/101 3,051,062 8/1962 Apel et al. 404/119 *l-z? 66 "AM I o i a;

PATENTEDJun 1 81am SHEET 1 OF 2 ap/w SHEETEBF 2 iii??? PI 5.1 EL

MACHINE FOR VIBRATING, LEVELING AND SCREEDING CONCRETE IN A FORMBACKGROUND OF THE INVENTION Basically, the art of casting concrete inroadways and the like is quite old and well known and has been developedto an acceptable state because the finished product must exhibit only atop surface, and perhaps upper portions of side edges, that areacceptable from the standpoints of appearance and structural soundness.This is mainly the result of pouring the concrete in a form in which thesides are of some suitable structure, such as steel, and the bottom ofthe form is simply the pre-excavated part of the earth, sometimessupplemented by any of the well-known aggregates. Consequently thebottom is never seen and no one ever knows what it looks like or whetherit is properly settled and formed until such time as the roadway isbroken up to be repaired or replaced, at which time, appearance, etc. isobviously of no consequence.

With the advent of pre-casting concrete slabs, walls, etc., the typicalroadway-building methods have been carried over, but these have provedto be inadequate because prior experience has failed to develop atechnique for perfecting an overall result that is satisfactory inappearance, durability, etc., primarily since, in the production of suchslabs, walls, etc., the form must include a bottom integrated with theform sides, and the end product must exhibit acceptable characteristicsfrom the bottom and sides as well as from the top. The problem is evenmore accentuated where the bottom of the form is configured to developribs, projections, etc., all of which must usually involve reenforcementin the form of rods, wires, mesh and the like.

The roadway techniques have demonstrated a markedly inferior product,because little attention has been paid to the bottom, and customaryvibration methods fail to take into account the need for settling theconcrete relative to reenforcing elements. For example, it is notunusual in a roadway system to employ manually controlled vibratorsknown as stingers, an elongated probe" that is thrust into the mass ofconcrete and vibrated in areas judged by the operator to be critical,but experience shows that the operator will, in his zeal to avoidentanglement between the stinger and reenforcing rods etc., consciouslyor otherwise avoid these areas, leaving critical areas replete withvoids, unbonded aggregate etc. This of course is totally unacceptable inthe pre-casting of slabs, walls and like structures.

SUMMARY OF THE INVENTION According to the present invention, and whenespecially adapted to pre-casting systems other than roadways, aprefabricated form having integral sides and a bottom is filled,leveled, vibrated and screeded by a self-propelled machine having therequisite elements to produce an end product that meets the moststringent requirements. Fundamentally, a main frame is carried byflanged wheels that ride and follow the form sides. The frame carries afront or leveling screed, ahead of which concrete is introduced. Thisscreed is vibrated to assure proper settling of the concrete and furtherhas a blade to push surplus concrete ahead. Each end of this screed isprovided with a batwing for urging laterally surplus concrete inwardlyand ahead of the blade. A rear screed follows the front screed and isreciprocated or otherwise moved in a plane parallel to or coincidentwith the desired finished surface and this screed assures the properfinish. Additionally, the form is vibrated by means acting on the formand not in the concrete itself, which eliminates guesswork peculiar tothe usual stinger.

The screeds are trailed by drawbars designed to develop the proper linesof draft forces, and the screeds are arranged for free vertical floatingover the concrete. In a preferred embodiment, the screeds are raised andlowered by two-way force-exerting means by which downward as well asupward forces may be exerted, the downward forces being availed of toelevate the main frame for various purposes, especially during lateraladjustment of the flanged wheels to adapt the machine to forms ofdifferent widths.

Further features in the improved design reside in rubber or equivalentmountings to isolate vibrational forces from possibly adversely affectedparts, a central control console enabling the operator to easilymanipulate the machine and its components, flexibility of use andoperation, reversibility of the drive means, drive to all wheels,telescopic shafting to accommodate lateral adjustment of the frameelements when different form widths are encountered, the ability of themachine to pass over joints, irregularities etc. with ease, and othercharacteristics that will be described in or apparent from the ensuingdescription of a preferred embodiment.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view, with intermediateportions omitted to conserve space.

FIG. 2 is a side elevation, with portions broken away and other partsshown in section.

FIG. 3 is a fragmentary section on the line 33 of FIG. 2.

FIG. 4 is a fragmentary view, on an enlarged scale, showing the mannerof connecting the rear screed to one of its lift devices.

FIG. 5 is a rear view of the structure shown in FIG. 4.

FIG. 6 is a fragmentary rear view showing a vibrator mounted on thefront screed.

FIG. 7 is an enlarged sectional view showing a raise and lower cylindermounting.

FIG. 8 is an enlarged front view with intermediate portions omitted,showing the mounting on the main frame of a form-vibrating device.

FIG. 9 is a side view of the structure shown in FIG. 8.

FIG. 10 is a schematic illustrating a representative control system.

DESCRIPTION OF A IREFERRED EMBODIMENT The machine has a main frame 20made up of a central structure 22 and opposite, parallel fore-and-aftside elements 24 carried on track guides, here in the form of fourflanged wheels 26, the left rear one of which is omitted from thedrawing. The wheels carry the frame 20 for advance and reverse travelover a form 28 (FIGS. 3 and 8) constructed of steel and having a bottom30 and opposite parallel sides 32 which provide tracks for the wheels.The flanges of the wheels lie respectively outside the tracks or sides32. In practice the form 28 may come in various widths, the most commonbeing 8 and 10', and differs from the typical roadway in that theroadway has no specially constructed bottom except the earth upon whichthe finished roadway rests. In the present case, it is not uncommon toprovide the bottom with elongated, upwardly opening channels 34 (FIG.8), and there may be several of these running parallel to the sides 32so that the finished product has ribs or stems.

The central structure comprises front and rear tubular cross members 36rigidly interconnected by a pair of fore-and-aft members 38, and eachside element 24 has rigidly united therewith front and rear inwardlyextending transverse members or elements 40 that telescopically fit therespective cross members 36 so that the side elements may be adjustedinwardly or outwardly relative to the central structure 22 toaccommodate forms of different widths. Suitable clamps or locking meansare provided at 42 to maintain the selected adjusted positions. screwthreaded cranks 44 are provided as means for adjusting the width ortread of the frame 20.

As best seen in FIG. 3, each side element 24 has depending box-like legs46 within the lower ends of which the associated flanged wheel 26 isjournaled, and each wheel has a sprocket 48 fast therewith. The crossmembers 40, like the cross members 36, are tubular and coaxially containcross shafting 50, interior portions of which are telescopic as shown at52 in F IG. 3 to accommodate transverse adjustment of the frame 20. Eachouter end portion of the shafting has keyed thereto a sprocket 54, andat each side of the machine an endless chain 56 is trained about thesprockets 48 and 54 as well as about a pair of idlers 58. The right handend of the rear shaft 50 has a second sprocket 60 keyed thereto and thissprocket is driven by a chain 62 from a sprocket 64 on a shaft driven bya reversible motor 66 mounted on the frame side element 24. The chainsand sprockets and motor thus provide drive means for advancing andreversing the frame in its travel over the form 28. The motor 66 ispreferably air-driven; although, this does not limit the invention.

Rigidly connected to and depending from the central structure 22 arefront, rear and intermediate hitch elements 68, 70 and 72, FIG. 1,showing that there are a pair of each. Each element has a plurality ofvertically spaced apart holes to provide different points of attachmentfor mechanisms drawn by the frame, and the elements are substantiallysymmetrically arranged so that trailing mechanisms may be selectivelyconnected thereto according to the direction of travel of the frame asdriven by the motor 66.

ln the present case, and considering that forward travel of the frame isfrom left to right as seen in F 108. l, 2 and 9, the mechanism or devicetrailed from the front hitch 68 is a front screed 74 having transverselyspaced apart connection points 76 including both a fore-and aft pivot 78and a rubber or equivalent bushing or mount 80 to which a pair ofdrawbars 82 are connected by a depending plate 84 and a second orforward depending plate 86 having a pivotal and rubberbushed connection88 to the screed just ahead of the mount 80. The front end of eachdrawbar 82 is pivotally connected at 90 to the associated front hitchelement 68 at a selected one of the adjusting holes, preferably suchthat the line of draft force is downwardly and rearwardly inclined.This, combined with other details to presently appear, assures that thescreed has the proper float and can pass over joints, etc. in the formtracks 30.

The screed 74 is preferably of rectangular box section and carries aheadof it a blade much like a dozer blade 92 for leveling concreteintroduced to the form ahead of the screed. Each outer end of the bladehas an angled batwing 94 to sweep excess concrete back into the form,and each batwing has a lower resilient strip 96 enabling the batwing toride over joints etc. in the track 30. For the purpose of settling theconcrete in the form ahead of the screed 74, a pair of vibrators 98 aremounted on the screed and the rubber mountings and 88 serve to isolatethe vibrations from the main frame 20. The vibrators may be of anysuitable type; e.g., as seen in the U.S. Pat. No. to Peterson 2,917,290,which like the motor 66, is preferably airdriven.

The screed 74 may be raised and lowered by means including a pair offluid motors 100, again preferably airpowered. Each motor is mounted onthe central structure 22 by means including rubber mounts 102 (FIG. 7),and the exterior end of the motor piston rod 104 telescopically fitswithin a sleeve 106 having a rubber-bushed connection 108 to the screed74 and further having a rubber or equivalent stop 110 at its bottom endagainst which the end of the piston rod may abut when down pressure isapplied by the cylinder. Normally, the piston rod is extended to aposition in which its head is spaced between the stop 110 and the bottomof the cylinder so that the screed has a limited amount of verticalfloat. At times, as when adjusting the width of the frame 20-or thetread of the wheels 26-it may be desirable to elevate the frame to clearthe wheels from the track. This may be done by raising the screed 74 andinserting blocks, say 6 inches l0 inches high, beneath the screed andthen applying a downward force against the screed and blocks byextending the piston, it being understood that each cylinder is of thetwo-way type. The mount 88 of course includes a transverse pivot toaccommodate raising and lowering of the screed as the drawbar 82 swingsin a vertical plane.

A rear screed 112, like the front screed 74, spans the form and, alsolike the front screed, has a length sufficient to cover the widest formover which the machine is intended to be operated, so that, whenadjusting the frame 20, it is not necessary to adjust the screed. As tothe front screed, the batwings 94 may be laterally adjustable to accordwith changing form widths. The rear screed is trailed by a pair ofdrawbars 114 from pivotal connections 116 with the intermediate hitchelements 72, and each drawbar has a combined pivot and rubber-bushedconnection 118 with the screed. In addition to the transverse pivot 116,the front drawbar connection includes a vertical pivot 120, because therear screed is capable of being reciprocated transversely of the fonn asa concrete finisher.

The means for reciprocating the rear screed is shown here as comprisingan air motor 122 having a depending shaft 124 to the lower end of whichis affixed a crank 126 connected by a transverse pitman 128 with thescreed. The pitman is provided with ball-joint connections toaccommodate float and raising and lowering of the rear screed by meansof a pair of rear air cylinders 130 which may be mounted to the centralframe structure 22 by means similar to those for those front cylinders100. Likewise, the piston rods 132 of the cylinders 130 are connected tothe rear screed by means of sleeves 134 having interior structure likethat of the sleeves 106. The lower end of each rear screed sleeve 134has a cross tube 136 within which is relatively loosely received amember in the form of a bail 138 attached to the rear screed and havinga substantial transverse extent to enable free reciprocation of the rearscreed (FIGS. 4 and 5). Down pressure for raising the frame by means ofextending the rear screed cylinders is available because the tubes 136can engage the tops of the bails to apply the downward force.

As a further means for assuring a properly finished product, the form 28is vibrated, preferably by means of at least a pair of vibrators 140carred by the main frame and operative against the upper outer portionsof the tracks or sides 30 (FIGS. 8 and 9). These vibrators may again beof the type referred to above.

Each vibrator 140 is rigidly affixed to an angle 142 which engages theupper outer comer of the respective track 30 and the angle is pressedagainst the track by force-exerting means such as any conventional airsprings 144 connected at one end to the angle and at its other end to asupport 146 connected to the main frame sides so that the vibrators actagainst the form just ahead of the front screed and just behind thefront wheels 26. Because of the fore-and-aft yieldability of the airsprings 144, the support carries front and rear abutments 146, includingrubber bumpers 148, engageable front and rear with the angle 142. Thecombination of the air springs and rubber bumpers isolates the mainframe from the forces developed by the vibrators 140. The vibrators areso mounted that their axes of rotation are angled, each on a line XX,which results in vibrational forces developed in inwardly and downwardlyinclined planes Y-Y intersecting the bottoms of the respective formchannels 34 (FIG. 8). This assures proper settling of the concrete inthe deeper parts of the form.

As already described, the vibrators and motors are preferably of theair-driven type and these may be controlled from a convenient controlpanel or console 150 at the front of the main frame, readily accessibleto the operator who also performs the duties of adding concrete,attending to the form, etc. A representative control system is shownrather schematically in FIG. 10, where the legends FV, RM, SV, DM, RCand FC denote the form vibrators 140, the reciprocating motor 122, thescreed vibrators 98, the drive motor 66, the raise and lower cylinders100 and 130 and the clamps or air springs for the vibrators 140, eachcontrolled by respective valves V V V V V and V all suitably connectedto an air supply line 152 in which is provided a safety valve V,. In atypical installation, a supply line 152 may run along each side of theform, being pressurized by a suitable central source of compressed air.Where two lines 152 are provided, connections may be made at either sideof the form according to the direction of travel of the machine, and itis preferred that such connections be made by means of self-sealingquick-couplers as suggested at 154. In the event of an emergency, thesafety valve V may be used to cut out all motors and vibrators.Obviously, the controls may be individually operated or ganged"according to the situations.

in instances where the machine is intended to be operated in a directionthe reverse of that described, the

front and rear screeds may be interchanged, the front screed beingconnected to the hitch element and the rear screed to the intermediatehitch 72. The hitch elements are such that other attachments may beconnected thereto in place of the screeds, or the rear hitch 70 may beused to tow, for example, a rotary brush or the like to clean the form28.

I claim:

1. A machine for vibrating, leveling and screeding concrete in a formhaving elongated parallel sides and a bottom, the sides providingtracks, comprising a main frame having guide means supporting the mainframe on and for advance along the tracks, drive means for advancing themain frame, a front screed transverse to and spanning the tracks, frontdrawbar means articulately connecting said screed to the frame foradvance therewith, a rear screed transverse to and spanning the tracks,rear drawbar means articulately connecting the rear screed to the framefor advance therewith, and each drawbar means extending downwardly andrearwardly from the frame to its screed so as to exert downwardly andrearwardly inclined draft forces on the respective screeds.

2. A machine for vibrating, leveling and screeding concrete in a formhaving elongated parallel sides and a bottom rigidly connected to thesides, the sides providing tracks, comprising a main frame having guidemeans supporting the main frame on and for advance along the tracks,drive means for advancing the main frame, a front screed transverse toand spanning the tracks, means connecting said screed to the frame foradvance therewith, a rear screed transverse to and spanning the tracks,means connecting the rear screed to the frame for advance therewith,means associated with and operative in advance of the front screed forleveling concrete introduced into the form ahead of said front screed,and form-vibrating means carried by the frame for advance therewith andengageable with the form sides.

3. The invention defined in claim 2, in which the form-vibrating meansis operative to exert forces transverse to the length of the form.

4. The invention defined in claim 2, in which the form-vibrating meansis operative to exert forces in planes transverse to and inclineddownwardly and inwardly relative to the length of the form.

5. The invention defined in claim 2, especially for use with a formhaving at least one upwardly opening channel running lengthwise thereof,further characterized in that the form-vibrating means exerts forces inplanes converging downwardly and inwardly and substantially intersectinga lower part of the channel.

6. A machine for vibrating, leveling and screeding concrete in a formhaving elongated parallel sides and a bottom, the sides providingtracks, comprising a main frame having guide means supporting the mainframe on and for advance along the tracks, drive means for advancing themain frame, a front screed transverse to and spanning the tracks, a rearscreed transverse to and spanning the tracks and spaced to the rear ofthe front screed, a front hitch element on the frame ahead of the frontscreed, an intermediate hitch element on the frame ahead of the rearscreed, a rear hitch element on the frame behind the rear screed, afirst drawbar connecting the front screed to the front hitch element, asecond similar drawbar connecting the rear screed to the intermediatehitch element, said drawbars and 7 8 hitch elements being so constructedand arranged the 7. The invention defined in claim 6, in which the firstand Second drawbars are merchangeable respec' drive means is reversiblefor selectively advancing and tively to the rear and intermediate hitchelements and to the rear and front screeds for operating the machine inthe opposite direction.

reversing the machine.

1. A machine for vibrating, leveling and screeding concrete in a formhaving elongated parallel sides and a bottom, the sides providingtracks, comprising a main frame having guide means supporting the mainframe on and for advance along the tracks, drive means for advancing themain frame, a front screed transverse to and spanning the tracks, frontdrawbar means articulately connecting said screed to the frame foradvance therewith, a rear screed transverse to and spanning the tracks,rear drawbar means articulately connecting the rear screed to the framefor advance therewith, and each drawbar means extending downwardly andrearwardly from the frame to its screed so as to exert downwardly andrearwardly inclined draft forces on the respective screeds.
 2. A machinefor vibrating, leveling and screeding concrete in a form havingelongated parallel sides and a bottom rigidly connected to the sides,the sides providing tracks, comprising a main frame having guide meanssupporting the main frame on and for advance along the tracks, drivemeans for advancing the main frame, a front screed transverse to andspanning the tracks, means connecting said screed to the frame foradvance therewith, a rear screed transverse to and spanning the tracks,means connecting the rear screed to the frame for advance therewith,means associated with and operative in advance of the front screed forleveling concrete introduced into the form ahead of said front screed,and form-vibrating means carried by the fraMe for advance therewith andengageable with the form sides.
 3. The invention defined in claim 2, inwhich the form-vibrating means is operative to exert forces transverseto the length of the form.
 4. The invention defined in claim 2, in whichthe form-vibrating means is operative to exert forces in planestransverse to and inclined downwardly and inwardly relative to thelength of the form.
 5. The invention defined in claim 2, especially foruse with a form having at least one upwardly opening channel runninglengthwise thereof, further characterized in that the form-vibratingmeans exerts forces in planes converging downwardly and inwardly andsubstantially intersecting a lower part of the channel.
 6. A machine forvibrating, leveling and screeding concrete in a form having elongatedparallel sides and a bottom, the sides providing tracks, comprising amain frame having guide means supporting the main frame on and foradvance along the tracks, drive means for advancing the main frame, afront screed transverse to and spanning the tracks, a rear screedtransverse to and spanning the tracks and spaced to the rear of thefront screed, a front hitch element on the frame ahead of the frontscreed, an intermediate hitch element on the frame ahead of the rearscreed, a rear hitch element on the frame behind the rear screed, afirst drawbar connecting the front screed to the front hitch element, asecond similar drawbar connecting the rear screed to the intermediatehitch element, said drawbars and hitch elements being so constructed andarranged the first and second drawbars are interchangeable respectivelyto the rear and intermediate hitch elements and to the rear and frontscreeds for operating the machine in the opposite direction.
 7. Theinvention defined in claim 6, in which the drive means is reversible forselectively advancing and reversing the machine.